﻿<!DOCTYPE html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title></title>
</head>
<body>
<script>

    //为什么传window
    //1.利于压缩
    //2.window为顶层，查找起来很慢，传入window，解决查找慢
    //为什么传undefined
    //1.undefined为window的属性，不是关键字，可以修改
    var undefined = 10;
    alert(undefined);
    (function (window, undefined) {
        



    })(window);



</script>
</body>
</html>